CRIME IN THE FAMILY

By LINDA WOLFE; Linda Wolfe is the author of ''Wasted: The Preppie Murder'' and ''Private Practices,'' a novel.

Published: April 22, 1990

REASONABLE DOUBT

By Philip Friedman.

487 pp. New York:

Donald I. Fine. $19.95.

It seems to me dead sure that nonfiction in general, and works about so-called true crime in particular, have profited by the much-touted blurring of the lines between fiction and nonfiction. At the very least, the employment of fictional techniques like dialogue, interior monologue and sequential action lends drama, depth and drive to a factual account. And in the best of such books (one thinks, of course, of Truman Capote's ''In Cold Blood''), an author's poaching in fiction's province - taking aim at character as well as events, bypassing excessive detail in favor of bagging the telling one, the emotional heart of the matter - can capture greater significance and power for a true story.

What is less certain is whether fiction has anything to gain by emulating nonfiction. Yet this is what Philip Friedman, a lawyer and the author of three previous novels, has done in ''Reasonable Doubt,'' a novel that reads more like a true crime story than a made-up one.

The protagonist of ''Reasonable Doubt'' is Michael Ryan, a widowed attorney whose only child, a son, has been murdered. Ryan's daughter-in-law, wealthy and sophisticated Jennifer Kneeland Ryan, is accused of the murder. Confoundingly, she asks Ryan to defend her; reluctantly, he says yes. In the course of the case, Ryan learns chilling and unsavory truths about both his dead son and his explosive daughter-in-law.

The plot is a suspenseful one. Did Jennifer really kill her husband? And whether she did or not, why is it that someone seems out to kill her? The technical details are interesting, and accurately described. They range from legal arguments for and against a family member's representing a relative, to the role of the press in affecting the way the courts handle a case, to the pretrial preparation and strategy that are almost more important in a criminal proceeding than the actual trial.

But unfortunately, most of the characters in ''Reasonable Doubt'' are stick figures, the familiar stuff of television law dramas, and the words they think and speak are cliches. There's Ryan, who is given to such private reflections as: ''He could not make peace with the shades of his wife and son until he first made peace with himself. And he sensed that this [letting himself think about them] was a major part of the process.'' There's Kassia Miller, a hard-boiled female attorney who eventually goes all mushy over Ryan and tells him: ''You put the bad guys behind bars, for heaven's sake. That's the great American myth, the white hats against the black hats, and you lived it.'' There's a judge named Anthony R. Corino, also known as Hang 'Em High Corino, who of course turns out to be a pussycat; and Jennifer Kneeland Ryan, the poor little rich girl, who says of her dead husband: ''You know what I really liked about Ned? He was smart, and he knew what he wanted.'' Her sinister father, Robertson Kneeland - we know he's sinister because he has a limousine upholstered in silky black leather and thick black carpet that's equipped with a bar, television and fax machine - says to his son-in-law, while that unfortunate is still alive: ''Listen, Sonny, this isn't some high school debate. This is real life.''

Worse than the dialogue are the scenes and descriptive sentences that bulge with unnecessary details. Ryan and Miller don't just order lunch, or order it from a nearby restaurant; they order it ''from one of the nearby restaurants whose delivery menus they had collected.'' Ryan doesn't just do his research in a law library, but in a ''law library his firm had co-ventured with two other law firms in the building.'' The details multiply and mount. It is Philip Friedman's appetite for minutiae that makes his novel resemble a factual account of a crime - one that includes all facts, however trivial, all testimony, however dull. This overinclusiveness, combined with his lack of interest in character, prevents ''Reasonable Doubt'' from being a viable work of fiction.